<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <input type="text" name="" id="">
</body>
<script>

 let timerId
 document.querySelector("input").oninput = function(){
     clearTimeout(timerId)

 timerId = setTimeout(()=>{
     console.log(this.value);
  },3000)
 }




</script>
</html>